The act of seeking a hot person out in any means possible. Stalking is meant to be innocent and doesn't always make the person a stalker.
Examples of stalking include searching the person on the internet, adding as a friend on social networks and wathcing their every move, clicking on their mom's profile to find out personal family information, casually asking in a conversation where they live, driving by their house repeatedly, getting their tag number, dropping by at their job, following the person through the grocery store... and the list goes on.